At times, it is necessary to provide an assembly for a transfer between a stationary means and a reciprocating means. The transfer may comprise electrical energy transfer, optical energy transfer, or a transfer of gaseous, and/or transfer of liquid substances. In general, to accomplish such a transfer, the stationary means and the movable means must be connected to each other by way of a plurality of lines, which must be routed such that they mate and participate in the relative movement between the stationary means and the movable means. Typically, such routing has been accomplished by employing a "dragchain assembly".
A dragchain assembly, comprises two or more chain bands of metal or plastic material which are interconnected by webs at longitudinally spaced locations. These webs hold the two or more chain bands in a defined distance, and hold the individual lines in a position corresponding to the particular shape of the dragchain. The dragchain may also consist of elements which are joined in the manner of chain links within which the lines are inserted.
Upon moving the reciprocating means, the end of the dragchain attached to the movable means is moved in the longitudinal direction of the dragchain relative to the dragchain end attached to the stationary means. As a consequence thereof, the position of the dragchain loop changes in the longitudinal direction of the dragchain. There is also a change concerning the individual chain links participating in the loop formation. When a specific dragchain length is exceeded, the upper chain length sags to such an extent that the upper chain length possibly is deposited on the lower chain length.
Dragchains are a complex and correspondingly expensive solution. The lines guided by them are subject to considerable mechanical loads. Due to the movement of the dragchain, and in particular, the migration of the location of the dragchain loop, friction is caused between the lines and the individual dragchain elements. In particular, friction is caused between the webs interconnecting the chain bands. Accordingly, provisions must be made so that the individual lines guided by the dragchain are all of equal length, otherwise, individual lines of the dragchain are subject to excessive tensile loads. Also, at both ends of the dragchain, the individual lines usually are connected to electrical connectors, accordingly, provisions must be made for a specific strain relief of the individual lines.
Due to the unsupported length of the dragchain, the upper chain length often drops onto the lower chain length, causing wear to the dragchain. When this is to be avoided, an intermediate ceiling in the form of a slide plate must be inserted in the guiding channel. This slide plate must be sufficiently strong to carry the upper chain length. However, the slide plate cannot extend across the entire moving distance of the movable means, otherwise, the dragchain loop would be hindered by the slide plate after only a short moving distance of the movable means. When a dragchain assembly is used having two dragchains moving in opposite directions, such a slide plate cannot be employed, except for the short distance between the stationary ends of the two dragchains moving in opposite directions.
In addition to the foregoing structural shortcomings of conventional dragchains, dragchain assemblies are very expensive.
Individual cabling, having no dragchain or other suitable supporting slide assembly, sustains very high friction and abrasion between overlapping cable portions. This friction prevents the overlapping portions of the cable to freely slide against each other, which may eventually cause a fracture of the cable and rapid wear of the cable jacket. Furthermore, high tensile and thrusting forces are necessary to be exerted on the cable in order to overcome the friction.
The foregoing illustrates limitations known to exist in present flexible cable carriers. Thus, it is apparent that it would be advantageous to provide an improved cable carrier directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.